Communications: Tin cluster anions (Snn−, n=18, 20, 23, and 25) comprise dimers of stable subunits

Abstract

Evolution of the electronic properties of clusters and the semiconductor-to-metal transition

Global optimization of clusters using electronic structure methods

“…Genetic algorithm Main-group elements and coinage metals Li, [117] Cs, [119] B, [118] Al, [138] Ga, [139] Si, [140] Sn, [130,[134][135][136] Pb, [141] P, [142] As, [142] Bi, [143] Cu, [126,144] Ag, [94,125,126] Au [94,125,126,145] Nanoalloys Na-Si, [127] Sn-Bi, [146,147] Ag-Cu, [126] Au-Cu, [126] Au-Ag [94,125] Oxide a and other systems Li-O, [148] Be-O, [149] Mg-O, [150,151] B-O, [152] Al-O, [153] Ce-O, [154] W-O, [155] Li-F, [156] Al-H, [157] B-C, [158] Li-Al-B, [159] H 2 O-H [160] Complex systems Ag-Lig, [161] Au-Surf, [131,162] Au-Pd-Surf [162] Basin hopping Homoatomic B, <...>…”

“…Reprinted from Ref. [130], with permission from American Institute of Physics. c) The golden Au atoms for the various cluster isomers are bond to the F-center.…”

“…20 For example, cationic, neutral, and anionic tin clusters have been studied extensively by combining GA-DFT with various experimental methods. [130,[134][135][136] In an interesting case study, Schooss and coworkers [130,136] investigated the structures of medium sized Sn cluster anions, combining GA-DFT calculations with trapped ion electron diffraction and collision-induced dissociation. Population sizes of 40 individuals and up to 32 "offspring" were required to locate several low energy isomers within 15-90 generations at the def-TVZP/TPSS [137] level of theory, to explain the experimental results.…”

“…[146,147] FP-GA studies for multielement systems are quite new and, consequently, it is not surprising that only a few examples exist so far (Table 1). Apart from the nanoalloys, to date mostly metal oxide species have been investigated by GA-DFT in combination with infrared (IR) spectroscopy, because they serve as model systems for oxide surfaces or , [130] and c) Au 8 /F/MgO [141] . a) The GM (I) and low energy isomers (II;III) exhibit planar, bowl-like, or double-wheel like structures which cannot be reproduced by EPs.…”

Cluster melting: new, limiting, and liminal phenomena

“…Their experiment was not based on direct calorimentry, but rather on mobility measurements that can sensitively probe structural distortion away from sphericity. As tin clusters in this size range were already known to be highly prolate, a finding which has been repeatedly demonstrated [28,64], it was possible to interpret the persistence of prolate geometries at temperatures of 50 K above the bulk melting temperature of tin (515 K) as evidence that these clusters remained in the solid state.…”